It is known that an organopolysiloxane having a (meth)acryl group at one terminal is synthesized by ring-opening polymerization of hexamethylcyclotrisiloxane. For example, Japanese Patent Application Laid-Open No. Sho-59-78236 describes a method for the synthesis of an organopolysiloxane having a (meth)acryl group at one terminal by subjecting hexamethylcyclotrisiloxane to ring-opening polymerization, wherein lithium trimethylsilanolate is used as a polymerization initiator, and terminating the polymerization by 3-(2-methacryloxy ethoxy)propyl dimethyl chlorosilane.
Further, Japanese Patent Application Laid-Open No. Hei-7-224168 describes a method for the synthesis of organopolysiloxane having a (meth)acryl group at one terminal by subjecting hexamethylcyclotrisiloxane to ring-opening polymerization in the presence of pentacoordinate silicon catalyst, wherein trimethylsilanol or 3-methacryloxypropyl dimethylsilanol is used as a polymerization initiator, and terminating each polymerization by 3-methacryloxypropyl dimethylchlorosilane or trimethylchlorosilane.
However, these one-terminal reactive organopolysiloxanes are siloxane polymers consisting of hydrophobic segments. There are few examples for a one-terminal reactive organopolysiloxane having a hydrophilic group (Japanese Patent Application Laid-Open No.2008-274278).
Polyoxyalkylene compounds having a hydrolyzable silyl group, which is reactive, at a terminal is described in Japanese Patent Publication No. Sho-59-25808 and Japanese Patent Publication No. Sho-61-29379, and are used as a hydrophilic silane coupling agent. However, these polyoxyalkylene compounds do not have a siloxane chain.
An organopolysiloxane having a hydrophilic group is a block copolymer composed of hydrophilic segments and hydrophobic segments. The hydrophilic segments associate with each other, and the hydrophobic segments associate with each other, resulting in microphase separation. Taking advantage of such a phenominon, this polysiloxane is used in cosmetics and various paints, but requires further improvements, such as an introduction of more-reactive group for applications which require durability.
Japanese Patent Application Laid-Open No. 2001-55446 and Japanese Patent Application Laid-Open No. 2008-202060 describe one-terminal reactive polysiloxanes having a hydrophilic group. However, in these one-terminal reactive polysiloxanes, the hydrophilic group is located between the block having a reactive group and the polysiloxane block. Therefore, in a case where the polysiloxane is used in paints, such a problem occurs that the hydrophilic group is covered with the siloxane segment, which prevents the microphase separation from occurring on a surface of a coating.
Patent Literature 1: Japanese Patent Application Laid-Open No. Sho-59-78236
Patent Literature 2: Japanese Patent Application Laid-Open No. Hei-7-224168
Patent Literature 3: Japanese Patent Application Laid-Open No. 2008-274278
Patent Literature 4: Japanese Patent Publication No. Sho-59-25808
Patent Literature 5: Japanese Patent Publication No. Sho-61-29379
Patent Literature 6: Japanese Patent Application Laid-Open No. 2001-55446
Patent Literature 7: Japanese Patent Application Laid-Open No. 2008-202060